A few weeks ago I purchased an Aeonium tabuliforme, and since then it has lost many of its leaves which have turned yellow and dropped off. I have it in bright light, I do not overwater it, and it is in well-draining soil. Please help!

Which of the leaves are yellowing and dropping? Typically, my Aeoniums start to drop the outer leaves when our temps are getting too warm. It will tighten the rosette, like curling inwards , slow down a bit in growth and will keep it that way, and resume more active growth when Fall season returns with its cooler temps . When I see this happening, I really am careful in watering, since the plant is in a semi-dormant phase.

Also, did you notice if the plant has made any bloomstalks? Aeonium tabuliforme is monocarpic, so it will naturally die after it blooms.